S U M M A R YVerticillium albo-atrum required C 0 2 for growth when glucose or glycerol was the sole carbon source but not when succinate or acetate was supplied. The yeast form of the fungus fixed 14C from NaH14C03 into extracellular metabolites (I to 2 %), low-molecular-weight intracellular components (I 7 %), lipids (3 %), nucleic acids (34 %) and proteins (42 %). The only radioactive protein components were aspartate (33 %), glutamate (33 %), arginine+lysine (22 %), and leucine+ isoleucine (6 %). Nucleic acid bases that contained appreciable 14C were uracil (27 %), cytosine (21 %), adenine (22 x), guanine (27 %) and thymine (4 %). Carbon dioxide fixation appeared to be important for the anaplerotic biosynthesis of fourcarbon intermediates and for purine biosynthesis.
Proteinase biosynthesis by Streptococcus liquefaciens, strain 31, may be obtained from an entirely synthetic medium. Adenine and uracil seem to satisfy best the purine and pyrimidine requirement while pyridoxal and riboflavin is the combination of vitamins that leads to maximal enzyme biosynthesis. Biotin and folic acid together, or thiamine, have an inhibitory effect on enzyme synthesis. The amino acid requirements for optimum activity are unaffected by the reduced number of vitamins and nitrogen bases present in the final medium as compared to the initial medium. A reduction in the number of vitamins (to pyridoxal and riboflavin), however, showed that only adenine and uracil gave the best response to the purine and pyrimidine demands for biosynthesis; prior to this, in the presence of a complete vitamin pool, several combinations of nitrogen bases yielded equal enzymatic activity. When proteinase synthesis is plotted against time, enzyme formation ceases at about 3 hours. The shape of the curve indicates a straight-line relationship after an initial lag period of 90 minutes.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.